Dynamic protrusions mediate crawling motility in Asgard archaea

Crawling motility is a hallmark of eukaryotic cells and requires a dynamic actin cytoskeleton, regulated adhesion and spatially organized signalling pathways 1 , 2 . Asgard archaea, which are considered the closest known prokaryotic relatives of eukaryotes, potentially encode these functions within their large set of ‘eukaryotic signature proteins’ 3 , 4 , 5 , 6 . The few cultivated members show a complex cell morphology, consisting of a central cell body from which several protrusions extend, filled with an actin-based cytoskeleton 7 , 8 . Here, live-cell microscopy of two organisms of the Lokiarchaea and Hodarchaea lineages 7 , 9 showed that they dynamically and greatly change their cell shape on a minute time scale and grow and retract their extensive protrusions with a speed of 1.5–4.8 µm min −1 , respectively. After adhering to a glass surface, cells use their protrusions to undergo active crawling motion.